Amplifiers are commonly used to provide gain to an input signal. For example, if a voltage amplifier has a voltage gain of 10, then an input signal of 50 millivolts (“mV”) applied to the voltage amplifier results in an output signal of 500 mV. An amplifier typically has a range in which the amplifier operates in a linear manner. For example, a voltage amplifier connected to a 5-volt power supply may be linear for outputs up to 4.5 volts. However, driving output voltages greater than 4.5 volts may force the amplifier into non-linearity, resulting in overload of the amplifier and thus potential inaccuracy. In addition to linearity and noise concerns that can affect accuracy, many amplifier circuits can also be susceptible to input offset. For example, even an input offset of a few millivolts can greatly affect the accuracy of the amplifier circuit.
Many amplifier circuits, such as instrumentation amplifiers, generate a current signal between two amplifier devices through a direct connected resistor. For a direct connection between the amplifier devices, i.e., for DC coupling, such amplifier circuits can generally operate without difficulty. However, if the gain in the amplifier circuit is high, then large offset can occur to decrease accuracy of the amplifier circuit. To address large voltage offset, AC coupling is often implemented, such as through connecting a capacitor between the amplifier devices. In most instances, the capacitor is provided external to the integrated circuit chip containing the amplifier circuits. As a result of an additional bond pad that is utilized and the accumulated stray capacitance, mainly due to the need to configure the bond pad to allow for the connection of the external capacitor, the capacitive loading of the external wiring connections becomes unequal. When the capacitive loading becomes unequal, the ability to achieve low, even harmonic distortion becomes extremely difficult to obtain.